docs: def write_representative_sequences_file(self, outname, outdir=None, set_ids_from_model=True):
          """Write all the model's sequences as a single FASTA file. By default, sets IDs to model gene IDs.
  
          Args:
              outname (str): Name of the output FASTA file without the extension
              outdir (str): Path to output directory of downloaded files, must be set if GEM-PRO directories
                  were not created initially
              set_ids_from_model (bool): If the gene ID source should be the model gene IDs, not the original sequence ID
  
          """
  
          if not outdir:
              outdir = self.data_dir
              if not outdir:
                  raise ValueError('Output directory must be specified')
  
          outfile = op.join(outdir, outname + '.faa')
  
          tmp = []
          for x in self.genes_with_a_representative_sequence:
              repseq = x.protein.representative_sequence
              copied_seq_record = copy(repseq)
              if set_ids_from_model:
                  copied_seq_record.id = x.id
              tmp.append(copied_seq_record)
  
          SeqIO.write(tmp, outfile, "fasta")
  
          log.info('{}: wrote all representative sequences to file'.format(outfile))
          self.genome_path = outfile
          return self.genome_path